Our perforated twinwall is a strong pipe with a ribbed outer wall and a smooth internal bore.Usually used in land drain applications under heavily trafficked areas or when a deeper installation is required, the ribs in the outer wall give the pipe excellent compressive strength, enabling it to withstand large forces of pressure.andnbsp;A range of bends, junctions and couplers accompanies each pipe size. Seals are not required to be used with the fittings when using perforated pipes.For a brief overview our twinwall system please watch the brief video below.